Immobilized Enzyme Based On Vegetable Oil-based Watreborne Polyurethane For CO₂ Conversion

Converting atmospheric CO₂ into chemical products has become an effective way to mitigate global warming.The enzyme-catalyzed CO₂ conversion has the excellent characteristics including high efficiency,high selectivity and mild reaction conditions.However,free enzyme is limited due to it's instability and difficulty to recover.In order to improve the reusability and stability of free enzyme,vegetable oil-based waterborne polyurethane was chosen as the material to immobilize enzymes due to environmental friend.3D bioprinting technology has the advantages including rapidness,high precision,and high biological activity in the field of immobilized enzymes.In this study,carbonic anhydrase and formate dehydrogenase were immobilized into oil-based waterborne polyurethane for CO₂ conversion through 3D bioprinting technology.The main contents are summarized as follows:1.The stable dispersion with castor oil-based anionic waterborne polyurethane was prepared.Carbonic anhydrase was immobilized into waterborne polyurethane coatings by electrostatic attraction between the anionic group of polyurethane and carbonic anhydrase based on 3D bioprinting technique.The enzyme-containing coating prepared by the 3D bioprinting technology is thinner,smoother and more uniform than the conventional coating method.The enzyme activity recovery of the prepared enzyme-containing coating is 5 times that of the conventional coating method.2.According to the characteristics of waterborne polyurethane molecular structure and the film formation characteristics of the coating,carbonic anhydrase was immobilized by an UV curing method.Modified carbonic anhydrases with the acryloyl chloride double bond were mixed with UV-curable waterborne polyurethane dispersion,in the presence of an initiator,UV irradiation triggers the curing to form a film.It was found that carbonic anhydrase was introduced into the coating in the form of covalent bonding.The stability and reusability of carbonic anhydrase were significantly improved after immobilization.The immobilized carbonic anhydrase retained 91%of original activity after repeated use for 10 times.3.Based on the immobilized carbonic anhydrase by UV-cured polyurethane coating,after the carbonic anhydrase and formate dehydrogenase?FDH?were modified by the acryloyl chloride double bonds,the co-immobilization of multiple enzymes in the polyurethane coating was achieved through covalent crosslinking with polyurethane molecular chains.The immobilized multi-enzymes were applied to the reaction of catalyzing the conversion of CO₂ to formic acid.The yield of formic acid obtained after reacting for 10 h was 1.5 times that of the immobilized single enzyme?FDH?.